Worries about the effect of the ash cloud pushed forward US President Barack Obama's planned departure from Ireland and he arrived on Monday night in Britain to begin a state visit.

Last year, ash from another Icelandic volcano caused 100,000 flights to be cancelled, stranding 10 million passengers and costing the industry an estimated $1.7 billion in lost revenue.

Iceland's President Olafur Grimsson told CNN the latest eruption was on a "monumental" scale but would not wreak the same havoc on aviation.

Copyright APP (Associated Press of Pakistan), 2011

Copyright Reuters, 2011